Question

Which type of soil or rock allows water to pass through them? A. impermeable C. permeable B. nonporous D. underground

Short answer

Permeable (Option C) allows water to pass through.

Step-by-step solution

Understanding Soil and Rock Properties

To solve the problem, we need to understand the terms used in the options. Soil and rocks can either be porous or nonporous, and permeable or impermeable. Porous materials have tiny holes or spaces (pores), and permeable materials allow water to flow through them easily.

Eliminating Incorrect Options

Option A, 'impermeable', means that a material does not allow water to pass through. Option B, 'nonporous', refers to materials without pores, meaning they do not allow water to pass through easily. Option D, 'underground', does not directly describe the ability of soil or rock to allow water to pass through.

Selecting the Correct Option

Option C, 'permeable', describes materials that allow water to pass through easily. Permeable soil or rock has interconnected pores that facilitate the flow of water.

Key concepts

Soil Properties

Soil properties are essential characteristics that determine the behavior of soil under various conditions. These properties can influence how soil interacts with water, air, and other substances. Understanding soil properties can help predict its suitability for construction, gardening, agriculture, and water management.

Key soil properties include:

• Texture: Describes the size of soil particles. Soil can be sandy, silty, or clayey, influencing its texture. Sandy soils typically have larger particles and allow faster water drainage.
• Structure: Refers to the arrangement of soil particles into aggregates or clumps, affecting air and water movement.
• Porosity: The volume of pore spaces between soil particles. Higher porosity usually means better water retention and permeability.
• Permeability: The ease with which water can flow through the soil. This is influenced by the size and connectivity of pores.

Soil properties are interconnected. For instance, a clayey soil might have a high water-holding capacity but low permeability, as its small pores prevent easy water flow.

Water Flow in Rocks

Water flow in rocks is primarily determined by the rock's porosity and permeability. These factors affect how groundwater moves through geological formations.

Rocks can be categorized based on their capacity to transmit water:

• Permeable rocks: These rocks have interconnected pore spaces, allowing water to flow through them easily. Examples include sandstone and limestone.
• Impermeable rocks: These have few or no interconnected pores, thus limiting water flow. Granite and clay are examples of such rocks.

The ability of rocks to allow water flow is crucial for the development of aquifers, which are natural underground water storage systems.
Water flow in rocks also affects erosion and the formation of geological features like caves and valleys. When water can move freely, it can dissolve or carry away rock material, changing the landscape over time.

Porous Materials

Porous materials are substances that contain numerous tiny holes or pores. These pores affect how substances like water, air, or chemicals interact with the material.

Characteristics of porous materials:

• Pore size: Can range from microscopic in materials like clay to much larger in things like pumice or sponge.
• Porosity percentage: Indicates the fraction of the material's volume that is open space. A higher porosity means more space for holding or transmitting fluids.
• Connectivity of pores: Determines if a porous material is permeable, meaning whether a fluid can move through it easily.

Porous materials are found naturally, such as in soil and rocks, as well as in man-made products like ceramics and filters. Understanding porosity and permeability in these materials is essential for applications ranging from construction to water filtration and environmental science.